Alteration of miR-362-5p and miR-454-3p expression elicits diverse responses in breast cancer cell lines

The heterogeneity of breast tumors presents a challenge in disease management, necessitating an understanding of the molecular mechanisms driving breast tumorigenesis. Aberrant expression of microRNAs is known to promote tumor growth and progression. Our previous RNA-sequencing dataset revealed the upregulation of miR-362-5p and miR-454-3p in breast tumors. We investigated potential role of miR-362-5p and miR-454-3p in breast cancer using MDAMB231 and MCF7 cell lines. The expression of miR-362-5p and miR-454-3p were altered in MCF7 and MDAMB231 using mimics and inhibitors. The effect on cell viability, cell cycle progression and migration was assessed using Alamar blue assay, flow cytometry and wound healing assay. Further, the expression of potential target genes were measured using real-time PCR. Our results indicated that an increased expression of miR-362-5p promoted cell growth and survival in MCF7, but decreased cell migration. In contrast, miR-362-5p overexpression reduced cancer cell growth, survival and migration in MDAMB231. Overexpression of miR-454-3p was oncogenic in both cell lines but suppressed migration in the aggressive cell line MDAMB231. Two microRNAs, miR-362-5p and miR-454-3p, were evaluated for functional activity in breast cancer cell lines and they showed increased proliferative signals and tumorigenic properties.